Medical image data, such as computed tomography (CT) image data, nuclear medicine image data and magnetic resonance (MR) image data, are commonly stored, e.g. encoded, in a standard image format for medical images, for example in accordance with a DICOM image format standard, e.g. in accordance with the NEMA DICOM PS3 standard, for example as specified in the NEMA DICOM PS3 2017a specification, and/or in accordance with the ISO standard 12052:2006 “Health informatics—Digital imaging and communication in medicine (DICOM) including workflow and data management.”
It is also known in the art that specific medical imaging technologies generate non-scalar image data, thus comprising a plurality of separate values, e.g. forming a vector value, for each image voxel (or pixel) location. These separate values may be indicative of different material properties of the imaged subject, or, at least, convey different or complementary information about the same imaged pixel or voxel location.
For example, in multi-energy CT imaging, e.g. spectral CT imaging or dual-energy CT imaging, different materials can be identified by analyzing multi-energy data acquired during the CT scanning. Thus, each pixel in the generated CT image may have pixel values associated therewith that correspond to one or more materials or chemical elements that can be identified, by applying, for example, material decomposition and related techniques known in the art. Furthermore, various properties of the materials, such as a mass fraction or a number of material units in each pixel (or voxel) can be calculated.
It is known in the art to handle material-specific data by generating and viewing DICOM-compatible images for each scalar component of such non-scalar, i.e. vector-valued, image data, e.g. each material, separately.
For example, the United States patent application no. US 2010/0014729 discloses a method for separating diagnostic content of x-ray images from non-diagnostic content to achieve an image reproduction and windowing. A plurality of radiological density images may be displayed, in accordance with a disclosed method, in a single viewing window by overlaying greyscale images of each radiological density image in a single display window.